1) Field of the Invention
The present invention relates to a logic circuit using hardware to process keyboard scanning, more especially to a microprocessing system applied to a computer, a mobile phone, an electronic dictionary and calculator using a pressed key to input the signal into a control circuit for conducting operation for an efficient detecting method of recognizing the locations and numbers of pressed keys.
2) Description of the Prior Art
The common and familiar method of keyboard recognition mainly has a diode disposed between an input and an output ports; the unidirectional current conduction of the diode detects whether a current is passing by for recognizing a valid signal of a presses key.
However, the abovementioned method for detecting whether there is a pressed key signal has to be added with one to a plurality of current conducting diode and that complicates the circuit detection; furthermore, the increased components also increase unnecessary power consumption; the degree of wearing of the microprocessing system in a computer, a mobile phone, an electronic dictionary and calculator using a pressed key to input the signal into a control circuit for conducting operation will also be increased.